Manage Site Accounts Tool not provided in SCCM 2012
SCCM 2007 included the Manage Site Accounts (MSAC) Tool which helped you manage your user-defined Windows accounts for a Site. This tool is no longer shipped with SCCM 2012 and should not be used with a ConfigMgr 2012 Site. All user account management in ConfigMgr 2012 should be performed through the ConfigMgr Console.